Particle Interactions with Matter and Detectors

Abstract

What does it mean to see a particle? From the epistemological point of view, to see an object means to detect the light reflected by its surface. The light is nothing else than a component of the electromagnetic radiation that can be detected by the human eye. Particles are so small that they cannot reflect visible light. We observe particles by detecting the emitted radiation when the particles interact with matter or fields. A particle detector is a translator that connects one of our sensory organs (or a computer) with the effects produced by interacting particles. The problems presented here show relevant cases of matter-particles interactions. Supplement 2.1 shows the multiple Coulomb scattering: charged particles traversing a medium are deflected by the superposition of many Coulomb scattering from individual nuclei. Supplement 2.1 presents the important case of the energy losses of high energy muons.